The present invention relates to a laundry prewash composition and preferably to such a laundry prewash composition which is aqueous in nature.
Numerous prewash compositions of the type generally contemplated by the present invention have been disclosed in the prior art. The need for such prewash compositions has long been known because of the general inability for common washing techniques to loosen or remove certain spots, stains or the like on various fabrics. Such spots and stains may be either oil soluble or water soluble and may appear upon a variety of textiles including cottons, synthetic fibers, mixed cotton and synthetic fibers, silks and wools for example.
Even where such washing techniques are carried out with relatively high temperatures, certain spots and stains on fabrics may be difficult to remove entirely in a single washing. It is for this reason that the use of prewash compositions has been adopted. Initially, such prewash compositions were formed from concentrated detergent, of the type normally used in the wash cycle, applied directly onto the fabric spots or stains. The soiled area of the textile with the concentrated detergent in place was then rubbed or otherwise treated in order to enhance action of the detergent upon the spots or stains. In these initial techniques, the detergent could be applied either directly in the case of a liquid detergent or by addition of small amounts of water to form a paste from dry detergents.
More recently, specific prewash compounds have been developed particularly for application to fabric spots and stains which would otherwise be difficult to clean by conventional washing procedures. The effectiveness of these early prewash compositions was commonly enhanced by the addition of substantial quantities of surfactants, for example, either anionic or nonionic, and/or various organic or hydrocarbon based solvents. These surfactants and solvents were employed because of their known ability to loosen or otherwise remove particular fabric spots and stains. Prewash compositions of the types available in the prior art tend to be either mixtures of one or more surfactants and a small amount of an organic solvent or solvents in a relatively large amount of water or mixtures of surfactants in hydrocarbon or other organic solvents with very little water. The latter type of product is commonly very effective on oil soluble stains while being generally more expensive.
Numerous prewash compositions including water as either a major or predominant component have been disclosed in the prior art and have been intended to resolve one or more problems arising because of the use of water as a component in the composition. For example, it is often difficult to maintain various prewash components in suspension in an aqueous system, particularly when the temperature of the composition tends to vary widely.
Augustijn U.S. Pat. No. 4,201,686 issued May 6, 1980, disclosed an aqueous liquid detergent composition containing mixtures of nonionic surfactants selected and combined in an aqueous medium for producing a stable composition which was nongelling at low temperatures.
Similarly, Canter U.S. Pat. No. 4,058,473, issued Nov. 15, 1977, disclosed a number of liquid detergent compositions containing potassium tallowate soap, nonionic detergent combinations forming at least 12 percent of the composition, hydrotropes, glycerin and other adjuncts for producing low temperature stable compositions.
Claybaugh U.S. Pat. No. 3,970,594 disclosed a number of dry granular cleaning compositions while stating that the compositions could be diluted to a liquid consistency. However, at the diluted strengths taught by Claybaugh, there would not appear to be a sufficient amount of the cleaning composition to afford any thickening.
Compositions of the type set forth in the above noted patents are contrasted for example to Berg U.S. Pat. No. 3,625,909 issued Dec. 7, 1971 which disclosed liquid spot removing agents consisting of at least about 50 percent total surfactant to provide proper detergency, from 2 to 10 percent by weight of a selected hydrotrope for improving clear solubility and viscosity behavior at low temperatures and from 2 to 50 percent by weight of an organic solvent with only 0 to 15 percent by weight water.
Another problem in both aqueous and nonaqueous prewash compositions is their relatively low viscosities which tend to prevent concentration of the prewash composition on the fabric spots and stains. In order to facilitate concentration of the prewash composition on the spots and stains, Felletschin et al U.S. Pat. No. 3,619,119 disclosed a spot treating composition comprising at least 29 percent total surfactant, 1 percent or more of a hydrotrope such as sodium xylene sulfonate and polyethylene glycol having a pasty composition suitable for being easily rubbed onto various textiles.
In a related vein, Kuzel et al U.S. Pat. No. 4,405,483 issued Sept. 20, 1983 disclosed various stable liquid detergent compositions containing from about 30 to about 88 percent by weight water, surfactants, builders, aluminosilicate particles being maintained in suspension by adjusting the pH of the composition in order to partially gelatinize the aluminosilicate material. However, it is noted that this patent was more concerned with maintaining the aluminosilicate particles as well as other detergent ingredients in a stable suspension within the composition rather than adapting the composition for localized treatment of fabric spots and stains.
Although various prior art disclosures and references have dealt with a number of problems encountered in prewash compositions, there has been found to remain a need for a prewash composition having suitable detergency for dealing with a variety of spots and stains normally encountered in various fabrics, the composition being thickened in order to enhance its localized application to the fabric spots and stains.